Dunkley, K. , Ioannou, C., Whittey, K., Cable, J., & Perkins, S. E. (2019). Cleaner personality and client identity have joint consequences on cleaning interaction dynamics. Behavioral Ecology, 30(3), 703-712. [arz007]. https://doi.org/10.1093/beheco/arz007 Publisher's PDF, also known as Version of record License (if available): CC BY-NC Link to published version (if available): 10.1093/beheco/arz007 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via Oxford University Press at https://doi.org/10.1093/beheco/arz007 . Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ Behavioral The official journal of the ISBE Ecology International Society for Behavioral Ecology Downloaded from https://academic.oup.com/beheco/advance-article-abstract/doi/10.1093/beheco/arz007/5303982 by University of Bristol Library user on 28 March 2019 Behavioral Ecology (2019), XX(XX), 1–10. doi:10.1093/beheco/arz007 Original Article Cleaner personality and client identity have joint consequences on cleaning interaction dynamics Katie Dunkley,a, Christos C. Ioannou,b, Kathryn E. Whittey,a Jo Cable,a,*, and Sarah E. Perkinsa,*, aSchool of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK and bSchool of Biological Sciences, University of Bristol, 106 Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK Received 24 October 2018; revised 24 December 2018; editorial decision 28 December 2018; accepted 7 January 2019. Mutualistic interactions involve 2 species beneficially cooperating, but it is not clear how these interactions are maintained. In many mutualisms, one species interacts with multiple species, and since partners differ in terms of the commodities they trade, partner identity will directly influence the decisions and behaviors of interacting individuals. Here, we investigated the consequences of within and between-species diversity on a model cleaner–client interaction in a natural environment, by quantifying the behavior of both partners. We found that the predominant Caribbean cleaner fish, the sharknose goby Elacatinus( evelynae), shows personality varia- tion as we documented repeatable individual differences in activity, boldness, and exploratory behaviors. Personality variation was associated with cleaner–client interactions: cleaner boldness and activity were significantly related to posing by clients and cleaning, respectively. Cleaner personality variation was also associated with the functional identity (sociality, mobility, body size, and trophic level) of clients posing and being cleaned. We thus demonstrate that partner identity can have consequences on mutualistic outcomes which will contribute to the context-dependency and highly heterogeneous patterns we observe at a population level. We also suggest that within- and between-species differences have consequences on partner choice, a feature that has been previously thought to be absent from these cleaner–client interactions. Key words: cleaner fish, coral reefs, mutualism, personality, repeatability, trade-offs. INTRODUCTION how much (McAuliffe and Thornton 2015). Currently, our under- Mutualistic interactions, where 2 species beneficially cooperate, are standing of mutualisms is hypothesized to be context-dependent observed in all ecosystems (Bronstein 2015), yet it is still not clear and highly heterogeneous (Bronstein 2015); so, investigating how how these interspecific interactions are maintained. Mutualisms individual partners influence mutualism outcomes will help to clar- often involve food resources (e.g., nectar and ectoparasites) being ify the dynamics and hence evolution of mutualisms under natural traded for a beneficial act (e.g., pollination; Landry 2012, parasite conditions. removal; Arnal et al. 2001), known as service–resource interactions Within an environment, service providers only make up a small (Holland et al. 2005), but not all partners are equal in terms of proportion of the biomass but interact with a disproportionately the commodities they trade (Palmer et al. 2015). These interspe- large number of other species (Sazima et al. 2010). As a result, cific interactions involve 2 individuals directly interacting at any mutualisms are often composed of networks of interacting spe- one time, and thus the behaviors and traits of one partner, could cies, with service providers carrying out ecosystem services, such directly influence the behaviors and traits of the other (Wolf and as pollination (Landry 2012) and health enhancing parasite con- Weissing 2012). Partner identity will hence underpin the behavioral trol (Clague et al. 2011; Waldie et al. 2011). Mutualists thus play responses and decisions of animals during these cooperative inter- a pivotal role in the structuring and functioning of ecological actions, influencing when individuals interact, with whom, and by communities (Floeter et al. 2007; Sazima et al. 2010; Quimbayo et al. 2018). An iconic, well-studied service–resource mutualism, the cleaner–client interaction, is observed ubiquitously on coral Address correspondence to K. Dunkley. E-mail: [email protected]. reefs (White et al. 2007; Leung and Poulin 2008). The mutualism *These 2 authors are the joint senior authors. involves a cleaner removing ectoparasites and other material from © The Author(s) 2019. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. Page 2 of 10 Behavioral Ecology the bodies of many client fish species (up to 132 different species; This prediction however has not yet been tested in a cleaning con- Grutter and Poulin 1998). Cleaning patterns, however, are inconsis- text, but personality variations have been shown to mediate other tent, with the same cleaner species showing preferences for different interaction types (e.g., predator–prey interactions; Pruitt et al. 2012, Downloaded from https://academic.oup.com/beheco/advance-article-abstract/doi/10.1093/beheco/arz007/5303982 by University of Bristol Library user on 28 March 2019 client types across studies. For example, cleaning gobies from the and service–service mutualisms; Schmiege et al. 2017). Client spe- genus Elacatinus prefer larger clients in some studies (e.g., Whiteman cies differ in their propensity to engage in cleaning interactions and Côté 2002b; Grutter et al. 2005; Silvano et al. 2012), but not (Côté et al. 1998; Bshary and Schäffer 2002), as well as the nutri- in others (e.g., Grutter and Poulin 1998; Arnal et al. 2000). These, tional content that they represent to cleaners (Eckes et al. 2015). like many other behavioral studies, focus on population patterns, These differences mean that different clients will provide asymmet- which assume all conspecifics exhibit the same traits, or that varia- ric benefits to the cleaning interaction. Larger (Poulin and Rohde tion around an average is random (Bolnick et al. 2011). Individuals 1997), group living and sedentary (Patterson and Ruckstuhl 2013) within many invertebrate and vertebrate populations vary consis- species, for example, are more prone to increased parasite loads. tently in their behavior (also known as animal personality varia- It is unknown whether individual cleaners respond asymmetrically tion; Reale et al. 2007), and this variation can play a major role in to client identities and vice versa, influencing interaction patterns. shaping population-level patterns of species interactions and other Here, to investigate the consequences of within and between- ecological processes (Wolf and Weissing 2012). There are 5 recog- species diversity on the outcome of mutualistic interactions, we nized animal personality traits (Reale et al. 2007), and for many quantified both cleaner and client behavior in situ. We observed the taxonomically distinct species, these traits can affect feeding and cleaning interactions between the predominant Caribbean cleaner foraging behaviors. The personality traits boldness and explora- fish, the sharknose goby (Elacatinus evelynae), and their reef fish cli- tion, for example, which can be broadly defined as an individual’s ents. These cleaner species rarely cheat by causing damage to client reaction to a risky (boldness) and new situation (exploration) (Reale bodies (Soares et al. 2008), and thus their cleaning behavior repre- et al. 2007), influence both an individual’s food intake and foraging sents a simpler system for studying cleaner–client interactions com- success (Ioannou et al. 2008; David et al. 2011). Bolder and more pared to the iconic bluestreak wrasse cleaners (L. dimidiatus, Côté exploratory individuals are expected to have increased metabolic and Soares 2011). Previous work has documented personality vari- demands since they are at an increased risk (e.g., to predation) and ation in (noncleaning) goby species (e.g., Magnhagen et al. 2014; utilize the environment